I. Field
The present disclosure relates generally to communication, and more specifically to techniques for operating in a wireless local area network (WLAN) that is co-located with Bluetooth.
II. Background
Many electronics devices support multiple communication protocols, which may also be referred to as radio technologies or air interfaces. For example, a laptop computer may use a wireless personal area network (WPAN) to connect to a wireless mouse, a wireless keyboard, and the like. The laptop computer may also have a device for communication with WLANs, which have become increasingly popular and are commonly deployed in homes, office buildings, coffee shops, libraries, and other public and private locations. A mobile device such as a cellular phone or a personal digital assistant (PDA) may also support multiple communication protocols such as cellular, WLAN, and Bluetooth. The mobile device may use WPAN to communicate with an earpiece and/or other devices. The mobile device may also be capable of providing email and Internet access as well as traditional cellular communication via the supported communication protocols.
A WPAN may utilize a communication protocol such as Bluetooth, which is a short-range communication protocol adopted as IEEE 802.15 standard by the Institute for Electrical and Electronic Engineers (IEEE). Bluetooth has an operating range of approximately ten meters. A WLAN may utilize any of the medium-range communication protocols in the IEEE 802.11 family of standards.
Some communication protocols operate on the same frequency band. For example, Bluetooth, IEEE 802.11, IEEE 802.11b, IEEE 802.11g, and some cordless phones all operate in the Industrial, Scientific and Medical (ISM) band between 2.4 giga-Hertz (GHz) and 2.4835 GHz. Bluetooth utilizes frequency hopping spread spectrum (FHSS). Cordless phones typically use proprietary radio techniques, which are permitted as long as they meet the regulatory requirements. Transmissions from a Bluetooth device are sent on 1 mega-Hertz (MHz) bandwidth and hop at a rate of 1600 times per second over 79 MHz in the ISM band. A WLAN device may implement IEEE 802.11b/g and may operate on a fixed frequency channel, which may be one of three non-overlapping frequency channels in the ISM band. In IEEE 802.11b/g, each frequency channel is 22 MHz for direct sequence spread spectrum (DSSS) or 16.7 MHz for orthogonal frequency division multiplexing (OFDM).
A Bluetooth device and a WLAN device may be co-located and in close proximity to one another. Co-location of these devices may entail using the same antenna, being located on the same circuit board or coupled circuit boards, being located on the same integrated circuit chip or coupled chip sets, being located within the same apparatus (e.g., a laptop computer or a mobile device), or any combination thereof. If the co-located devices are both operational, then there is some likelihood (approximately 28% chance) that a Bluetooth transmission will be sent on the frequency channel used by the WLAN device and would then interfere with a WLAN transmission.
When the Bluetooth and WLAN devices are co-located, a signal transmitted from one device may saturate a low noise amplifier (LNA) in a receiver of the other device, which may then cause the receiver to be desensitized. Thus, if the WLAN device is receiving a packet at the same time that the Bluetooth device is transmitting, then the transmit power of the Bluetooth device may spill into the receiver of the WLAN device and desensitize the receiver. The desensitization of the receiver may cause degradation in performance, loss of data, failure in communication, and/or other deleterious effects.
There is therefore a need in the art for techniques to avoid deleterious effects due to interference when a Bluetooth device and a WLAN device are co-located.